Modeling Urban Flood Inundation and Recession Impacted by Manholes

Abstract

Urban flooding, caused by unusually intense rainfall and failure of storm water drainage, has become more frequent and severe in many cities around the world. Most of the earlier studies focused on overland flooding caused by intense rainfall, with little attention given to floods caused by failures of the drainage system. However, the drainage system contributions to flood vulnerability have increased over time as they aged and became inadequate to handle the design floods. Adaption of the drainages for such vulnerability requires a quantitative assessment of their contribution to flood levels and spatial extent during and after flooding events. Here, we couple the one-dimensional Storm Water Management Model (SWMM) to a new flood inundation and recession model (namely FIRM) to characterize the spatial extent and depth of manhole flooding and recession. The manhole overflow from the SWMM model and a fine-resolution elevation map are applied as inputs in FIRM to delineate the spatial extent and depth of flooding during and aftermath of a storm event. The model is tested for two manhole flooding events in the City of Edmonds in Washington, USA. Our two case studies show reasonable match between the observed and modeled flood spatial extents and highlight the importance of considering manholes in urban flood simulations.

Innovations in Best Practices: Approaches to Managing Urban Areas and Reducing Flood Risk in Reggio Calabria (Italy)

“…The urban environment has a series of specific characteristics where urban structures may interact with the drainage system when it fails leading to flooding. The network of streets, for example, can function as a network of channels, when storm drains or channels overflow; walls can work as weirs; unexpected reservoirs may arise from public squares, basements, and even buildings, in general; flows in the drainage system may be reversed by backwater effects [43,44]. It is particularly important to model urban watersheds, coping channels, and storm drains networks with surface flow representation.…”

Assessment of Sponge City Flood Control Capacity According to Rainfall Pattern Using a Numerical Model After Multi-source Validation

“…The models include the Strom Water Management Model (SWMM), MIKE SHE, Soil and Water Assessment Tool (SWAT), and the Institute of Hydrology Distributed Model (IHDM). For example, Merhawi et al simulated urban flood inundation and recession affected by manholes [12], while Wu, et al [13] simulated urban flooding by coupling the SWMM and LISFLOOD-FP; Bai et al [10] used the SWMM to study low-impact development (LID). Although simulation is efficient, its reliability depends on accurate data from local hydrological monitoring stations.…”

Application of Macroscopic Fundamental Diagram under Flooding Situation to Traffic Management Measures

“…Global climate change has induced rainfall extremes in terms of frequency, duration, pattern, and intensity in many cities of developing countries [1]. As a result, urban flooding is one of the major challenges due to intensified rainfall events and inadequate urban engineering infrastructures [2,3]. For example, in the Bangkok metropolitan region (BMR), average total annual rainfall measured by the Thai Meteorological Department exceeded 2000 mm and caused road floods.…”